Abundance ratios of silicon to iron in clusters and groups look similar to each other in \(r<r{500}\) 
(see §REF ), and the silicon mass in poorer systems has a lower value than those in larger systems (the same trend as for the iron mass, caused by the lower gas mass). Because significant fractions of oxygen and silicon are mainly synthesized by SNcc, they are good indicators to estimate the amount of massive stars in the past. [1]} calculated the oxygen and silicon MLRs under the assumption of the Salpeter initial mass function with the slope of the power-law shape to be \(-2.35\) . If we assumed the silicon to iron abundance ratios to be \(\sim 1\)  up to the virial radius [2]}, [3]}, the expected silicon mass to light ratios (SiMLR) in rich clusters agree with the estimate derived by [1]}, as shown in [2]} and Sasaki et al. (2021). However for groups neither iron nor silicon have been observed yet out to and beyond \(r_{500}\)  with the exception of a handful of systems. To study the metal enrichment history of the ICM and IGrM, we need to measure oxygen profile, mainly produced by SNcc, to the virial radius and beyond since the whole clusters and group include the metals synthesized in the cluster and group formation phase.
To summarize, in order to progress in the understanding of the chemical enrichment of both groups and clusters, we need to measure the gas and metal MLRs to the virial radius for both clusters and groups to high redshift of \(z\sim 2\)  with the next generation of X-ray instruments (see §).
